There is a need to efficiently and reliably protect sensible optical and/or electronic apparatuses, which are housed on board of satellites and generally on space vehicles. For example, in the particular field of satellite space telescopes, there is a need to protect sensible parts pertaining to optics of said telescopes, both from undesirable contaminations by materials which may for example take place during launch or during initial orbit injection phase of satellite, or when crossing a region of space having a high density of space detritus, and for shielding the same in a selective way from undesirable and/or damaging radiations, for example direct solar radiation.
Known art solutions envisage the use of a tubular screen, called “aperture baffle”, which is disposed along the optical axis of telescope and which has an end aperture, to which a transversal closing device is associated, such as for example a circular port, which is rotatably hinged to the tubular screen and may be rotated out of the viewing field of telescope, during active phase of use of telescope. This solution is for example implemented on board the X-ray telescope called XMM, developed by ESA (European Space Agency).
Other known solutions envisage use of inflatable closing devices, such as for example the solution described in U.S. Pat. No. 3,850,504, or use of bistable rotatable closing devices, which may rotate around an axis parallel to optical axis, for moving between a closing position and an opening position, such as for example the solution described in U.S. Pat. No. 5,258,874.
The above indicated solutions of the known art have various drawbacks in terms of reliability, efficiency, structural complexity (for example, they require a high number of actuators), or bulk, to the point that there seems no reasonable use, in terms of feasibility and economic viability, of such solutions in so called “Large Telescopes”—space telescopes, in which the diameter of section to be protected generally exceeds approximately 4 meters, especially when, as in the so called “Mirror” telescopes, two protective devices are required, which are associated to upper part and lower part of optical system, respectively.